The Origin of the Architecture of the Solar System

2012 ◽  
Vol 20 (2) ◽  
pp. 276-290
Author(s):  
Michael Perryman
Keyword(s):  
Solar System ◽  
Giant Planets ◽  
The Moon ◽  
Central Importance ◽  
Impact Cratering ◽  
Planetary Satellites ◽  
Formation And Evolution ◽  
The Masses ◽  
Modern Astronomy ◽  
Asteroids And Comets

This article relates two topics of central importance in modern astronomy – the discovery some 15 years ago of the first planets around other stars (referred to as exoplanets), and the centuries-old problem of understanding the origin of our own solar system, with its planets, planetary satellites, asteroids, and comets. The surprising diversity of exoplanets, of which more than 500 have already been discovered, has required new models to explain their formation and evolution. In turn, these models explain, rather naturally, a number of important features of our own solar system, amongst them the masses and orbits of the ‘terrestrial’ and ‘gas giant’ planets, the presence and distribution of asteroids and comets, the origin and impact cratering of the Moon, and the existence of water on Earth.

Exploring the Solar System

2018 ◽  
Author(s):  
Karel Schrijver
Keyword(s):  
Solar System ◽  
Planetary Systems ◽  
Interplanetary Dust ◽  
Terrestrial Planets ◽  
The Moon ◽  
System P ◽  
Asteroids And Comets

In this chapter, the author summarizes the properties of the Solar System, and how these were uncovered. Over centuries, the arrangement and properties of the Solar System were determined. The distinctions between the terrestrial planets, the gas and ice giants, and their various moons are discussed. Whereas humans have walked only on the Moon, probes have visited all the planets and several moons, asteroids, and comets; samples have been returned to Earth only from our moon, a comet, and from interplanetary dust. For Earth and Moon, seismographs probed their interior, whereas for other planets insights come from spacecraft and meteorites. We learned that elements separated between planet cores and mantels because larger bodies in the Solar System were once liquid, and many still are. How water ended up where it is presents a complex puzzle. Will the characteristics of our Solar System hold true for planetary systems in general?

scholarly journals Scenarios of giant planet formation and evolution and their impact on the formation of habitable terrestrial planets

2014 ◽  
Vol 372 (2014) ◽  
pp. 20130072 ◽  
Author(s):  
Alessandro Morbidelli
Keyword(s):  
Solar System ◽  
Giant Planet ◽  
Giant Planets ◽  
Terrestrial Planets ◽  
Evolutionary Patterns ◽  
Eccentric Orbits ◽  
Earth Like Planets ◽  
Large Eccentricity ◽  
Formation And Evolution ◽  
Orbital Instability

In our Solar System, there is a clear divide between the terrestrial and giant planets. These two categories of planets formed and evolved separately, almost in isolation from each other. This was possible because Jupiter avoided migrating into the inner Solar System, most probably due to the presence of Saturn, and never acquired a large-eccentricity orbit, even during the phase of orbital instability that the giant planets most likely experienced. Thus, the Earth formed on a time scale of several tens of millions of years, by collision of Moon- to Mars-mass planetary embryos, in a gas-free and volatile-depleted environment. We do not expect, however, that this clear cleavage between the giant and terrestrial planets is generic. In many extrasolar planetary systems discovered to date, the giant planets migrated into the vicinity of the parent star and/or acquired eccentric orbits. In this way, the evolution and destiny of the giant and terrestrial planets become intimately linked. This paper discusses several evolutionary patterns for the giant planets, with an emphasis on the consequences for the formation and survival of habitable terrestrial planets. The conclusion is that we should not expect Earth-like planets to be typical in terms of physical and orbital properties and accretion history. Most habitable worlds are probably different, exotic worlds.

Exoplanets, 2003–2013

Daedalus ◽  
2014 ◽  
Vol 143 (4) ◽  
pp. 81-92
Author(s):  
Gáspár Áron Bakos
Keyword(s):  
Solar System ◽  
Aspect Ratio ◽  
Extrasolar Planets ◽  
Large Fraction ◽  
The Sun ◽  
The Moon ◽  
Short Period ◽  
Giordano Bruno ◽  
Formation And Evolution ◽  
Orbital Periods

Cosmologists and philosophers had long suspected that our sun was a star, and that just like the sun, other stars were also orbited by planets. These and similar ideas led to Giordano Bruno being burned at the stake by the Roman Inquisition in 1600. It was not until 1989, however, that the first exoplanet – a planet outside the solar system – was discovered. While the rate of subsequent discoveries was slow, most of these were important milestones in the research on extrasolar planets, such as finding planets around a pulsar (a compact remnant of a collapsed star) and finding Jupiter-mass planets circling their stars on extremely short period orbits (in less than a few Earth-days). But the first decade of our millennium witnessed an explosion in the number of discovered exoplanets. To date, there are close to one thousand confirmed and three thousand candidate exoplanets. We now know that a large fraction of stars have planets, and that these planets show an enormous diversity, with masses ranging from that of the moon (1/100 that of Earth, or 0.01M⊕) to twenty-five times that of Jupiter (25MJ, or approximately 10,000M⊕); orbital periods from less than a day to many years; orbits from circular to wildly eccentric (ellipses with an “eccentricity” parameter of 0.97, corresponding to an aspect ratio of 1:4); and mean densities from 0.1g cm−3 (1/10 of water) to well over 25g cm−3. Some of these planets orbit their stars in the same direction as the star spins, some orbit in the opposite direction or pass over the stellar poles. Observations have been immensely useful in constraining theories of planetary astrophysics, including with regard to the formation and evolution of planets. In this essay, I summarize some of the key results.

Jovian Planets

1999 ◽  
Author(s):  
Yuk L. Yung ◽  
William B. DeMore
Keyword(s):  
Solar System ◽  
Atmospheric Chemistry ◽  
Solar Nebula ◽  
Bulk Composition ◽  
Distinct Group ◽  
Giant Planets ◽  
Ion Chemistry ◽  
Nitrogen And Phosphorus ◽  
Jovian Planets ◽  
The Masses

The four giant planets in the outer solar system, Jupiter, Saturn, Uranus, and Neptune, are a distinct group by themselves. The essential astronomical and atmospheric aspects of these planets are summarized in table 5.1. The significance of this group in the chemistry of the solar system is briefly pointed out in chapter 4. These planets are composed primarily of the lightest elements, hydrogen and helium, which were captured from the solar nebula during formation. The planets have rocky cores made of heavier elements. In the case of Jupiter and Saturn the mass of the gas greatly exceeds that of the core, whereas for Uranus and Neptune the masses of gas and core are comparable. Due to the enormous gravity of the giant planets, little mass has escaped from their atmospheres. Hence, the bulk composition of these planets provides a good measure of the initial composition of the solar nebula from which they were derived. Of all planetary bodies in the solar system, the constituents of giant planets are the closest to the cosmic abundances of the elements. The chemistry of the atmospheres of the giant planets is interesting for the following reasons:… 1. chemistry in a dominantly reducing atmosphere 2. interplay between photochemistry and equilibrium chemistry 3. ion chemistry in polar auroral regions 4. heterogeneous chemistry of aerosols 5. chemistry of meteoritic debris 6. lack of a planetary "surface"… We briefly comment on these reasons in this section. Each topic will receive a more detailed treatment in later sections. First of all, the atmospheres of the Jovian planets are more than 90% hydrogen and helium. Since helium is inert, the atmospheric chemistry is dominated by hydrogen. Therefore, we would expect the most stable compounds of carbon, oxygen, nitrogen, and phosphorus to be CH4, H2O, NHa, and PHs. This is in fact confirmed by the available observed composition of the bulk atmospheres of these planets. However, in the upper atmospheres of these planets, the composition is controlled by photochemistry.

The formation and evolution of the Solar System

2002 ◽  
Vol 10 (2) ◽  
pp. 171-184
Author(s):  
THÉRÈSE ENCRENAZ
Keyword(s):  
Solar System ◽  
Kuiper Belt ◽  
Giant Planets ◽  
The Sun ◽  
Silicate Material ◽  
Surface Information ◽  
Origin And Evolution ◽  
Short Period ◽  
Formation And Evolution ◽  
Main Components

Astronomers have built the main components of a scenario for the formation of the Solar System. Small planetary bodies accreted others by collisions within a rotating protoplanetary disk that formed at the same time as the Sun. While terrestrial planets near the warming Sun could accumulate only solid metallic and silicate material, the giant planets formed from ice and gas at lower temperatures. Each planet and satellite then followed its own specific evolution, depending upon the properties of its atmosphere and/or surface. Information about the origin and evolution of the Solar System is also provided by the comets, which can be considered as frozen fossils of the Solar System's early stages. On the borders of the outer Solar System, beyond the orbit of Neptune, the newly discovered Edgeworth–Kuiper belt is probably the reservoir where short-period comets are formed.

scholarly journals Crustal porosity reveals the bombardment history of the Moon

2021 ◽  
Author(s):  
Ya Huei Huang ◽  
Jason Soderblom ◽  
David Minton ◽  
Masatoshi Hirabayashi ◽  
Jay Melosh
Keyword(s):  
Solar System ◽  
Surface Expression ◽  
Orbital Evolution ◽  
Terrestrial Planets ◽  
The Moon ◽  
Planetary Evolution ◽  
History Of ◽  
Giant Impacts ◽  
Formation And Evolution ◽  
Lunar Basins

Abstract Planetary bombardment histories provide critical information regarding the formation and evolution of the Solar System and of the planets within it. These records evidence transient instabilities in the Solar System’s orbital evolution, giant impacts such as the Moon-forming impact, and material redistribution. Such records provide insight into planetary evolution, including the deposition of energy, delivery of materials, and crustal processing, specifically the modification of porosity. Bombardment histories are traditionally constrained from the surface expression of impacts — these records, however, are degraded by various geologic processes. Here we show that the Moon’s porosity contains a more complete record of its bombardment history. We find that the terrestrial planets were subject to double the number of ≥20-km-diameter-crater-forming impacts than are recorded on the lunar highlands, fewer than previously thought to have occurred. We show that crustal porosity doesn’t slowly increase as planets evolve, but instead is generated early in a planet’s evolution when most basins formed and decreases as planets evolve. We show that porosity constrains the relative ages of basins formed early in a planet’s evolution, a timeframe for which little information exists. These findings demonstrate that the Solar System was less violent than previously thought. Fewer volatiles and other materials were delivered to the terrestrial planets, consistent with estimates of the delivery of siderophiles and water to the Moon. High crustal porosity early in the terrestrial planets’ evolution slowed their cooling and enhanced their habitability. Several lunar basins formed early than previously considered, casting doubt on the existence of a late heavy bombardment.

Concluding remarks

1981 ◽  
Vol 303 (1477) ◽  
pp. 379-381 ◽  
Keyword(s):  
Solar System ◽  
Comparative Studies ◽  
The Moon ◽  
Present Value ◽  
Impact Cratering ◽  
Water Ice ◽  
System A ◽  
The Difference ◽  
Dust Grain ◽  
The Way

A predominant aim of planetary exploration is to discover as much as possible about the origin of the Solar System. Therefore it is appropriate that the closing paper by Dr H. Reeves should be explicitly about this. Of course, almost every paper has implicitly provided constraints upon models for the formation; many are already familiar, but the recent work reported here renders them more severe or precise than before. The discussion prompts, in particular, the following considerations. In regard to terrestrial planets and the Moon and other large satellites, much is being learnt from recent comparative studies of surface features, of possible effects of volcanism, and of the physics of impact cratering. After taking account of differences due to the presence or absence of various sorts of atmosphere and of the consequences of the different values of surface gravity, the ‘geologies’ of the various bodies are still surprisingly different. Some of the differences that have been described are undoubtedly owing to the presence or absence of water in various states. This feature must surely be an important clue to the way in which the bodies were assembled. For instance, one cause of the difference between Earth and Venus is probably the circumstance that, if as generally supposed the solar luminosity had about 70 % of its present value in the early stages of the Solar System, a water-ice coating on a dust grain (assumed to behave as a small blackbody) at the Earth’s distance would remain frozen, but at the distance of Venus it would be melted. This must make a considerable difference to the way in which water was originally incorporated into the structures of these two planets

The Origin of the Moon

1962 ◽  
Vol 14 ◽  
pp. 149-155 ◽  
Author(s):  
E. L. Ruskol
Keyword(s):  
Chemical Composition ◽  
Solar System ◽  
The Moon ◽  
The Earth ◽  
The Difference ◽  
Origin Of The Moon

The difference between average densities of the Moon and Earth was interpreted in the preceding report by Professor H. Urey as indicating a difference in their chemical composition. Therefore, Urey assumes the Moon's formation to have taken place far away from the Earth, under conditions differing substantially from the conditions of Earth's formation. In such a case, the Earth should have captured the Moon. As is admitted by Professor Urey himself, such a capture is a very improbable event. In addition, an assumption that the “lunar” dimensions were representative of protoplanetary bodies in the entire solar system encounters great difficulties.

The Origin of the Moon and its Relationship to the Origin of the Solar System

1962 ◽  
Vol 14 ◽  
pp. 133-148 ◽  
Author(s):  
Harold C. Urey
Keyword(s):  
Solar System ◽  
The Moon ◽  
The Past ◽  
The Earth ◽  
Short Period ◽  
Origin Of The Moon

During the last 10 years, the writer has presented evidence indicating that the Moon was captured by the Earth and that the large collisions with its surface occurred within a surprisingly short period of time. These observations have been a continuous preoccupation during the past years and some explanation that seemed physically possible and reasonably probable has been sought.

The Long View of Planetary Systems

2018 ◽  
Author(s):  
Karel Schrijver
Keyword(s):  
Solar System ◽  
Milky Way ◽  
Planetary Systems ◽  
Giant Planets ◽  
Milky Way Galaxy ◽  
Population Statistics ◽  
The Past ◽  
General Terms ◽  
The Galaxy ◽  
The Universe

How many planetary systems formed before our’s did, and how many will form after? How old is the average exoplanet in the Galaxy? When did the earliest planets start forming? How different are the ages of terrestrial and giant planets? And, ultimately, what will the fate be of our Solar System, of the Milky Way Galaxy, and of the Universe around us? We cannot know the fate of individual exoplanets with great certainty, but based on population statistics this chapter sketches the past, present, and future of exoworlds and of our Earth in general terms.

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